Tension damper



Dec. 16, 1958 N. E. KLEIN 2,354,566

TENSION DAMPER Filed June 14, 1954 2 Sheets-Sheet 1 INVENTOR.

NORMAN E KLEIN BY WZJVZM 'ATTORN EY N. E. KLEIN TENSION DAMPER Dec. 16, 1958 2 Sheets-Sheet 2 Filed June 14, 1954 FIG-3- FIG.- 2-

INVENTOR.

NORMAN E. KLEIN BY mx/zw FIG-4- ATTORNEY TENSION DAMPER Norman E. Klein, Pendleton, S. C., assignor to Deering Milliken Research Corporation, Pendleton, S. (3., a corporation of Delaware This invention relates to motiondampers and more particularly to mechanical damping means suitable for use with yarn tension regulators and the like.

Yarn tension regulators are employed in the textile industry in conjunction with twisting apparatus, plying apparatus, and in many other instances. A most satisfactory form of tension regulator comprises a stationary yarn engaging member and a movable yarn engaging member cooperating therewith so that the tension in the yarn is regulated by movement of the movable member with respect to the stationary member, and while there are other types of tension regulators, substantially all have at least one movable member.

It is known that any tension regulator with a movable member tends to overcontrol if it is constructed to have a reasonable degree of sensitivity and it has been previously suggested that such regulators mightadvantageously be equipped 'with'dampingmeans. Littleprogress in this direction has been made, however, since there has not been available a simple damping means suitable for use with tension regulators and because of the difficulties encountered in providing a device of suitable dimensions and with satisfactory operating .characteristics for use with such mechanisms.

It is a primary object of this invention to provide improved damping means suitable for use with yarn tension regulators and the like.

It is a further object of the invention to provide damping means which can be inverted without the loss of damping fluid and in which the damping fluid does not become contaminated by dirt, lint and fly.

A further object of the invention is to provide a damping chamber with a flexible arrangement. for receiving an agitator such that negligible restraining force arises from resilient counteractions when the agitator is moved with respect to the chamber.

These as well as other objects of the invention are accomplished by a novel damping means comprising in combination an agitator or the like adapted to move in correlation to the movement of a member the motion of which is to be damped, a .closed chamber adapted to receive at least a portion of the agitator means, and substantially non-resilient means adapted to permit movement of the agitator means with respect .to at least a portion of the chamber.

It has been .found that if the force required to move the agitator with respect to the damping chamber is due in large part to the resiliency of the seal between the agitator and the chamber, effective damping is not obtained, and that for best results the resiliency of the agitator mounting should account for no more than about of the force required to move the agitator at velocities encountered in normal operation. If not more than about 10% of the force required to move the agitator, at average agitator velocities, is due to the resiliency of the agitator mounting, the mounting is considered in this specification andclaims to be"substantially non-resilient.

Several preferred embodiments of the invention will 2,864,566 Patented Dec. 16, 1958 now be described with reference to the accompanying drawings in which:

Figure 1 is a sectional view of a preferred embodiment of the invention;

Figure 2 is a sectional view ofa second embodiment of the invention;

Figure 3 is a sectional view of another embodiment of the invention; and

Figure 4 is a sectional view of still another embodiment of the invention.

With reference to the drawings in greater detail there is illustrated in Figure 1 the upper part of a pedestal such as may be employed in a'textile twisting machine of, for example, the type disclosed in my copending U. S. application Serial Number 244,812, filed September .1, 1951, now Patent No. 2,811,013. The reference numeral 19 indicates the outer housing of the pedestal which is supported by the platform of the twister, not'zillustrated. L0- cated partially within the sleeve or outer housing 10 is a cylindrical member 11 with .an exposed extension :12 of smaller diameter. The member 11 constitutes the pedestal proper and serves as ahousing for the yarn tension regulating device generally indicated by the reference numeral 13. A collar.14 threaded .into the upper end of housing 10 serves to properly .secure the member 11 in operating position.

The tension regulator .13 comprises a stationary member 15 which is rigidly "secured by any suitable means such as screw 16 to the cylindricalmember 11. Cooperating with the stationary yarn engaging member15 is a movable yarn engaging member '17 which is urged toward the stationary member .by any suitable means such as spring 18. When a strand of yarn is threaded between the two members 15 and 17, the output tension in the yarn tends to remain constant with large variations in input tension since the spring 18 is so disposed that the force with which movable member 17 is urged toward stationary member 15 decreases as the distance between the two members is increased. The tension in spring 18 may be varied by movement of a collar 19 threaded onto the upper end of extension 12.

Movable member 17 is supported by a pivot arm 20 the upper end of which is rigidly 'afiixed to a plate 25 secured to the back of member 17 by any suitable means such as by screws 26 and 27. The lower end of pivot arm 20 is provided with a pair of knife edges 28 (only one of which is illustrated) .resting in .a pair of notches 29 on opposite sides ofthe upper end of a cylindrical platform 30. This arrangement permits limited pivotal movement of member 17 about knife edges 28.

Attached to pivot arm 20 in close proximity to knife edges 28 is an agitator rod 31 which extends upwardly'in a plane substantially parallel to that in which the pivot arm 24 is movable. .Enclosing the free end of agitator 31 is a fluid chamber, generally indicated by the reference numeral 32, which comprises a tubular member 33 provided with a close fitting cap 34. The tubular member 33 is rigidly secured in position by any suitable means such as for example a bracket 40 attached to member 11 by screws 41 and 42. Secured to the lower end of tubular member 33 by any suitable means such as by clamp 43 is an elongated flexible member 44 made from any suitable material such as neoprene. The flexible member 44 is provided with an orifice at 45 of such size as to permit entry of the agitator 31 into the chamber 32 but to prevent the loss of damping fluid from the chamber.

In operation, the yarn tension regulator 13 is threaded with a strand of yarn and chamber 32 is filled with any viscous liquid such as for example a silicone fluid sold under the trade name Dow Corning 200 Fluid. When movable member 17 is pivoted about the axis of knife edge 28 because of the variations of tension in the strand of yarn, it will be apparent that agitator means 31 will move in correlation to the movement of pivot arm 20. It will also be seen that the agitator means 31 not only is pivoted with respect to the longitudinal axis of chamber 32 by the movement of pivot arm 20 but that agitator means 31 is also moved laterally with respect to the longitudinal axis of the chamber. The flexible member 44 accommodates both the lateral and pivotal movement of agitator means 31 while the rigid member 33 insures that when the agitator means is moved there will actually be a circulation of the fluid in the chamber rather than mere deformation of the chamber wall.

Since it is desirable that the resiliency of the system be as low as possible and since this necessitates as little lateral movement as possible of the portion of the chamber adjacent the point of entry thereinto of the agitator means 31, it will be seen that it is advantageous that the point of entry of the agitator means into chamber 32 be as near the axis of rotation of pivot arm 20 as possible. It has been found that for best results, the distance of the point of entry of the agitator into the chamber from the axis of rotation of the pivot arm should be not more than about Vs the effective length of the agitator when the limits of movement are not more than about 20 and in this specification and claims when the point of entry of the agitator means into the fluid chambet is within this distance it is referred to as being within close proximity of the axis of rotation of the pivot arm. Under these conditions, the resiliency of the flexible member 44 is very lowso that almost the entire force necessary to move the agitator means 31 is due to the damping action of the fluid in the container. The arrangement is thus capable of exerting near maximum efliciency in damping the movement of the member 17.

Figure 2 illustrates another embodiment of the invention wherein a damping means is employed with a yarn tension regulator. Only a section of the pivot arm of the tension regulator means is illustrated but the remain der of the tension regulator means can be the same as illustrated in Figure l. The reference numeral 46 indicates a cylindrical member Within which the damping means is positioned. The pivot arm 47 extending from the movable regulator element (not illustrated) is provided with a pair of knife edges 48 (only one of which is illustrated) resting in notches 49 in the upper edge of a platform member 50.

An elongated agitator 55 is attached to pivot arm 47 in close proximity to the knife edge 48 and extends upwardly in a plane substantially parallel to that in which pivot arm 47 is adapted for movement. free end of agitator 55 is a fluid chamber, generally indicated by the reference numeral 56, comprising a rigid tubular member 57 having an orifice in its lower end. The orifice is provided with a resilient grommet 58 made of any suitable material such as neoprene and is adapted to receive the agitator means 55. The chamber 56 is pivotally attached at its upper end to member 46 by means of a pivot pin 59 and a tab 60 so that it is free to pivot in substantially the same plane as that in which the agitator rod 55 is adapted for movement.

In operation the chamber 56 is filled with a viscous fluid to at least substantially cover the agitator 55. When pivot arm 47 is moved about the axis formed by knife edge 48, the chamber is pivoted about the axis of pin 59 because of the lateral movement of the agitator 55 at its point of entry into chamber 56. As will be seen, the rubber grommet serves only as a means to permit the agitator 55 to move pivotally with respect to the longitudinal axis of chamber 56 while pivot pin 59 permits lateral movement of the agitator at its point of entry into chamber 56.

Figure 3 of the drawings illustrates an embodiment of the invention suitable for use with a yarn tension regulator and again only the pivot arm of the regulator is illustrated. The embodiment of Figure 3 difiers from Enclosing the those previously described in that in place of providing means to permit lateral movement of the agitator at the point of its entry into the chamber, lateral movement of the agitator at point of entry is substantially eliminated by a construction which places this point on the axis of rotation of the movable yarn engaging member.

In Figure 3 there is indicated by the reference numeral 61 a tubular member constituting a part of the pedestal of a textile twisting device, and within the member 61 is partially illustrated a pivot arm 62 of a yarn tension regulator such as described above. The pivot arm 62 has a bifurcated lower extremity with the legs 63 and 64 resting on opposite sides of a cylindrical support member 65. The supporting ends of legs 63 and 64 are sharpened into knife edges at 66 and 67 and rest in a pair of suitable notches in the upper edge of the member 65.

Supported by a bracket 68 secured to the inner wall of the tubular member 61 by any suitable means such as by screw 69, is a fluid chamber generally indicated by the reference numeral 70. The chamber 70 comprises a tubular body portion 71, a close fitting cover 72, and a flexible diaphragm 73 adapted to close the lower end of the chamber. The diaphragm 73 is secured in place by a washer 74 and a shoulder nut 75 threaded onto the end of tubular member 71. The chamber 70 should be so positioned that the center of diaphragm 73 lies on a line running between the knife edges on legs 63 and 64 for reasons that will be made more apparent by subsequent paragraphs.

Attached at either end to the legs 63 and 64 by any suitable means such as by brazing is a cross member 76 which extends downwardly into a recess 77 in member 65 so that it passes below the lower end of chamber 70. An agitator 78 is carried by the cross member 76 and extends upwardly into chamber 70 through a centrally positioned orifice in diaphragm 73.

In operation, the chamber 70 is filled with a damping fluid to at least cover the agitator 78. When the arm 62 is pivoted on the knife edges 66 and 67, the agitator 78 is moved through the damping fluid but since the point of entry of the agitator into the damping chamber exactly coincides with the axis of rotation of arm 62 and therefore with the axis of rotation of agitator 78, there is substantially no lateral movement of the agitator at its point of entry into the damping chamber and the diaphragm 73 need only accommodate the pivotal movement of the agitator. This it is capable of doing with only a negligible restraining force resulting from resilient counteractions.

Figure 4 of the drawings illustrates still another em bodiment of the invention suitable for use with a yarn tension regulator, and again only the pivot arm of the regulator has been illustrated. The pivot arm, indicated by the reference numeral is positioned within a cylindrical member 86 which constitutes a part of the pedestal of a textile twisting machine. Mounted Within the member 86 is a platform member 87, the upper peripheral rim of which provides a pair of grooves 88 (only one of which is shown) positioned on opposite sides of the rim for the seating of corresponding knife edges 89 on pivot arm 85.

Rigidly positioned with respect to cylindrical member 86 by any suitable means such as bracket 90 and screws 91 and 92 is a rigid tubular member 93 which forms the body of a fluid chamber generally indicated by the reference numeral 94. The tubular member 93 is provided with a close fitting cap 95 for its upper end thereby forming an inverted well which encloses the free end of an agitator rod 96 attached by its lower end to the pivot arm 85. Near the point of its attachment to pivot arm 85, the agitator 96 is provided with a flange 97 of sub stantially the same diameter as tubular member 93. The flange 97 is connected to tubular member 93 by a flexible bellows 98 which completes the chamber 94. The cylindrical bellows 98 can be attached to cylindrical member 93 and flange 97 by any suitable means such as for example by cementing.

In operation, the chamber 94 is filled, to a level sufficient to substantially cover the upper end of agitator rod 96, with a viscous liquid such as a silicone fluid. When the pivot arm is moved about the axis of knife edge 89, agitator rod 96 is moved accordingly through the viscous liquid in chamber 94 thus providing the desired damping action. It will be seen that the tubular bellows 98 provides for both the lateral movement and pivotal movement of agitator rod 96 with respect to tubular member 93.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In a yarn tensioning device having a first yarn engaging member, a second yarn engaging member, and a pivot arm attached to said second member whereby said second member is capable of limited movement about an axis remote therefrom, improved damping means comprising in combination elongated agitator means rigidly attached by one end vto said pivot arm in close proximity to said axis and extending substantially parallel to the plane in which said pivot arm is movable, a fluid chamber enclosing a major portion of said agitator means and having a flexible fluid-tight seal at the point of entry of said agitator means into said chamber, said fluid-tight seal being disposed in close proximity to the pivot axis of said pivot arm, and said agitator means being fixed against substantial longitudinal movement along its length and being movable angularly about said axis in substantially angular synchronization with said pivot arm.

2. In a yarn tensioning device having a first yarn engaging member, a second yarn engaging member and a pivot arm attached to said second member whereby said second member is capable of limited movement about an axis remote therefrom, improved damping means comprising in combination an elongated agitator means attached by one end to said pivot arm in close proximity to said axis and extending substantially parallel to the plane in which said pivot arm is movable, a rigid, elongate-d fluid container adapted to enclose the free end of said agitator means, said chamber being pivotally se cured at one end and said chamber having an orifice in the unsecured end, and a flexible grommet in said orifice adapted to receive said agitator means and to permit pivotal movement of said agitator means with respect to said chamber, said grommet engaging said agitator at a point in close proximity to the pivot axis of said pivot arm to thereby provide substantially non-resilient means for permitting relative movement of said agitator with respect to said chamber.

3. In a yarn tensioning device having a first yarn engaging member, a second yarn engaging member, and a pivot arm attached to said second member whereby said second member is capable of limited movement about an axis remote therefrom, improved damping means comprising in combination elongated agitator means attached by one end to said pivot arm and extending through said axis substantially parallel to the plane in which said pivot arm is movable, a rigid tubular container open at one. end and adapted to enclose the free end of said agitator means and a flexible diaphragm covering the open end of said container, said diaphragm having an orifice to receive said agitator means positioned substantially on said axis, whereby when said pivot arm is moved with respect to said container there is substantially no lateral movement of said agitator at the point of contact with said diaphragm and substantially non-resilient means is provided for permitting relative movement of said agitator means with respect to said chamber.

4. In a yarn tensioning device having a first yarn engaging member, a second yarn engaging member, and a pivot arm attached to said second member whereby said second member is capable of limited movement about an axis remote therefrom, improved damping means comprising in combination elongated agitator means attached by one end to said pivot arm in close proximity to said axis and extending substantially parallel to the plane in which said pivot arm is movable, a rigid tubular container open at one end and positioned to enclose the free end of said agitator means, a flange on said agitator means, said flange being carried by said agitator means at a point in close proximity to the pivot axis of said pivot arm, and a flexible tubular corrugated sleeve forming a fluidtight connection between said flange and the open end of said container to thereby provide non-resilient means to permit relative movement of said agitator with respect to said chamber.

5. In a yarn tensioning device having a first yarn engaging member, a second yarn engaging member, and a pivot arm attached to said second member, whereby said second member is capable of limited movement about an axis remote therefrom, improved damping means comprising an upstanding rod rigidly secured at its lower end to said pivot arm in close proximity to the pivot axis thereof, an elongated fluid container enclosing a major portion of said rod, said container including a rigid upper portion and an elongated, tapered, readily flexible lower portion, said lower portion forming, at

References Cited in the file of this patent UNITED STATES PATENTS 2,222,847 Kent Nov. 26, 1940 2,776,805 Klein Ian. 8, 1957 FOREIGN PATENTS 200,630 Switzerland Jan. 2, 1939 

